I am going to freshen up the 500" Wedge in the Cuda this winter and plan on putting a 518 behind it when I put it back in.

Would you use a lock-up converter or not? And why. I understand that there are some restrictions on which lock-up converter can be used with the conversion bell housing.

The Cuda has 3.91s and a streetable 4,000 stall PTC in it now. If it is worth it, I don't mind buying another converter. 55 MPH is about 2,800 RPM now and there is no problem driving a couple of hours like that. The tranny does not get hot.

But I was wondering if the lower RPM that the overdrive would have it at at that speed would cause too much heat without a lock-up converter.

Anyone with experience with this have an opinion?

I believe you can only use a lock up converter on a lock up trans.

for that much power i'd get a non lockup.

Or be very carful not to put to much power to it when it's locked up. Can you set up a 518 to control OD and lockup seperatly?

I believe that your selection will also be determined by converter availability. Meaning...Im not sure that you can get a 4k flash lock up vert for the 518?

You may want to talk with some of the people that work with the diesel 618s about the availability of high torque clutches for lockup converters. Your stroker is getting close to diesel torque, but pulls more rpm. The lockup should only be used for part throttle cruise, so some throttle/ vacuum/trans pressure switch(es) should be setup to control that.

From the casual manner in which you mention putting a 518 in your 'Cuda over the winter, I am torn between two assumptions:

1. You are a master fabricater and won't have any problems slicing and dicing the torsion bar crossmember to get the transmission to fit.

or,

2. You have no idea of the challenges that lie before you.

So, which is it? One thing for sure, it's not a bolt-in swap!

Regarding the lock-up converter: There are two schools of thought, both valid. It is possible to use a regular converter, it is also possible to use a professionally built lockup converter. Either one will work, but if you go lockup you need to have someone build it who is familar with them.

There are lockup converters behind Diesels that make nearly twice the torque that your engine will. The torque converter clutch just has to be built for the job.

R.

The reality is that the majority of the time the converter would be locked up you won't have your foot in it, you'll just be cruisin' so the converter clutch doesn't have to be extra beefy. Even then, if it's properly setup, the converter will unlock with heavy throttle.

My buddy has one behind a strong 440. He built it and controls OD and CC with toggles on the console. Shifts very nice and yes OD/CC is only on when highway cruising. Run's easy mid 12's in street trim...shifter in drive You will want someone to build you a converter that works with your combo. I don't recall who did his..but it flat out works!!

I guess I should have said that I certainly do not expect the LU or the OD to hold any where near full power. It will only be for cruising along at light throttle.

As for requiring a master fabricator, there are adapter tranny mount brackets out there and I can surely cut the bell off of the 518 in preparation for bolting on the adapter bell. There are several very good and informative threads that will be invaluable for this.

A 518 core is $150 at the pick a part yards when they pull it, and I plan to test fit it before I spend the coin to beef it up. So if the wheels do fall off this project, I am not in up to my ears in it.

I am just curious about 2 things mainly;
First, with 4,000 stall and 3.91s, will the cruise RPM be so low that there will be enough slip in the converter without LU to give me too much heat while cruising.
Second, what would you guys run and why? LU or non LU. And if the LU, what are the restrictions that I would run into?

PTC has been building my converters and do a super job. I will talk to them also, but just wanted some opinions here first.

And if need be, I can back off the stall speed. We do not run the KOS circuit much any more. But would like to ready if it picks back up.

Thanks for the input, guys! I really appreciate it.

I am going to be running a 618 in my challenger. I have already cut off the bell. I am not sure if I am going lockup. The diesel converter is a lot larger than the 727 and with an ultra bell obviously we are going to have to run a stock size 727 converter. I have not done much research but I am not sure if there will be enough space to put clutch material to hold high hp applications.

Be sure to slip in a gas engine governor if you haven't already. 3200 rpm shift points aren't much fun.